The contract objectives include the design, fabrication, and qualification by in vitro and in vivo testing of a completely implantable left heart assist system capable of reliably assuming the required cardiac load for periods of two years. Specifically, the system would consist of a seamless dual chambered blood pump, fabricated from Avcothane or Avcomat elastometers and based on the existing Avco left heart blood pump (LHBP); an electrohydraulic energy converter based on the existing University of Utah system but incorporating a mechanical switching valve to allow the Utah system to operate in a non-reversing mode; and an implantable miniaturized control system based on hydraulic pressure sensing and R-wave detection. The workscope includes system design and analysis, blood pump development, energy converter development, system integration, system characterization, and system life and reliability testing.